Shock Absorber Dual Piston Flow Limiter Stability
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Solution Overview
Problem
Existing shock absorbers with double pistons face issues of instability due to soft washers causing unpredictable deformation, leading to vibrations and noise, and difficulties in fitting main pistons on the piston rod without restricting damping medium flow or complicating the fitting/removal procedure.
Innovation Solution
The shock absorber design incorporates a first flow limiter that is rigid and axially inflexible, acting as a non-return valve with a sealing washer configuration that includes radially inward lugs for improved centering and reduced flow resistance, and an intermediate part with radially extending ducts for enhanced damping medium flow and structural rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If soft flexible washers are used as flow limiters, then flow resistance is reduced and damping medium can pass easily, but the washers become unstable and deform unpredictably causing vibrations and noise
Solution Approach 1:
The patent changes the physical parameters of the flow limiter by transitioning from soft flexible material to a rigid structure with axial flexibility. The rigid body with axial slot maintains flexibility in the flow direction while providing structural stability, eliminating unpredictable deformation and vibrations.
Solution Approach 2:
The rigid flow limiter is segmented with axial slots that allow controlled movement and flexibility. This segmentation provides the necessary compliance for damping medium flow while maintaining overall structural integrity and stability.
2Ease of manufacture
If main pistons are mounted on piston rod with separate intermediate part, then fitting and removal is simplified, but flow paths become misaligned creating reduced flow area and unwanted restrictions
Solution Approach 1:
The intermediate part is merged with the piston rod to form an integrated structure. The through-hole in the intermediate part is aligned with the cavity in the piston rod, creating a continuous flow path without misalignment issues, while maintaining ease of assembly and disassembly.
3Loss of energy
If large area is provided for damping medium flow from pressurization tank, then flow resistance is minimized, but this creates unwanted restrictions in the flow between pressurization tank and intermediate chamber
Solution Approach 1:
The flow path is extended into the axial dimension with a through-hole in the intermediate part that connects to the cavity in the piston rod. This dimensional extension allows large flow area without creating lateral restrictions, optimizing the flow from pressurization tank to damping chambers.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration stabilizes the shock absorber dynamics, reduces vibrations and noise, and simplifies the fitting/removal of main pistons while maintaining low flow resistance and leak-tightness, allowing for adjustable damping characteristics.
Implementation Method 1
a first flow limiter (11, 12) which acts as a non-return valve and prevents flow through the pressurization ducts (9, 10) in a direction away from one of the damping chambers (C1, C2) to the intermediate chamber (8)
Implementation Method 2
The damping is realized through deformation of a second flow limiter created by a collection of flexible first washers 15, 16
Implementation Method 3
The first flow limiter is rigid and inflexible in the axial direction and has the form of a sealing washer which has an inner and an outer edge with respective extent in the radial direction, as well as a certain extent, preferably 0.2-0.5 mm, in the lateral direction
Implementation Method 4
The spacer sleeve 24 bears against an inner face A4i, A5i of the main piston 4, 5, and the inner edge 11b1, 12b1; 11b2, 12b2, of inner diameter d11i, d12i, of the first flow limiter 11, 12 is designed to slide against the outer face 24a of the spacer 24
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 3a~3c
AI summary
The invention relates to a shock absorber (IM comprising a damping-medium- filled damping cylinder (2) divided into a first and a second damping chamber (Cl, C2) by a main piston device made up of a first (4) and a second main piston (5). In the main pistons are with continuous ducts (9, 10; 13, 14) delimited in a direction of flow by first and second flow limiters (11, 12; 15, 16), mounted on a piston rod (3). The piston rod has an axial Iy extending and continuous cavity (7), through which damping medium can flow between a pressurized chamber (6a) into a pressurization. reservoir (6) and a respective damping chamber (C1/C2). The damping medium flows via an interspace (8), delimited by the first and the second main piston { 4, 5 ), in the main piston device out into a respective damping chamber (C1/C2) via pressuriaation ducts (11, 12) delimited by the first flow limiters (H1. 12). The first flow limitere (11, 12) lift axially from the main piston (4, 5) with substantially maintained external form in the opening process, so that a flow path is created both between the main piston (4, 5) and the whole or parts of the inner periphery (llbl, 12bl; Ilb2, 12b2) of the first flow lipiiter (11, 12), as well as between the main piston (4f 5) and the outer periphery (11a, 12a) of the flow limiter.